Difference between casting & forging
Difference between casting & forging
(OP)
My client requires gate valve with wedge 316SS (forging) but my principal is offering CF3M (casting). Can any one advise me if I can accept this. My principal says performance is the same for casting & forging. They intend to use casting because of less cost. The specs is 6" gate valve with A351 CF3M Body/Bonnet, Trim 10





RE: Difference between casting & forging
The twisted bits of iron used for railings and such are "wrought iron" which is actually pretty much steel. It doesn't help that there's more iron in steel than in cast iron. The nomenclature was dreamed up over the years before they really knew what they were doing.
Also, just about all the springs I have ever seen are steel, twisted into shape. Anyway, the question has been answerd cast metals are poured into shape; forged ones are pounded to shape.
My focus: Alloy Valves Duplex Valves Monel Valves Inconel Valves Titanium Valves Hastelloy Valves
RE: Difference between casting & forging
My focus: Alloy Valves Duplex Valves Monel Valves Inconel Valves Titanium Valves Hastelloy Valves
RE: Difference between casting & forging
Internal flaws are likely to be discovered during the forging process, where the plastic flow induced by the forging hammer will probably open any flaw and make it visually detectable.
Mike Halloran
Pembroke Pines, FL, USA
RE: Difference between casting & forging
The pressure, actual service and the 'branch experience' for valvetype and material selection would very much influence the choice. The requirement for forged material obviously has a (historical?) background. The experience with cast materials could be negative, perhaps for a particular brand? The requirement could also have been set a bit high, but anyway all consequences must be considered by a revision of a material/quality revision. The cost for failure is always higher than a smaller amount 'saved' for an altered single component.
RE: Difference between casting & forging
Perhaps your supplier could provide performance history for his product on the same, exact application.
As info - Within a given "family" of materials, depending on method of manufacture, there can be subtle differences in metallurgy, but significant difference in corrosion resistance. I have first hand experience with a particular application, where wrought 316L (ASTM A312 WP316L) or forged 316L (A182 F316L) will fail, whereas cast 316L (A351 CF3M) performs satisfactorily.
donf
RE: Difference between casting & forging
RE: Difference between casting & forging
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Difference between casting & forging
However, If I am your customer, I may stick with forging to minimize the risk.